1. Technical Field
The present invention relates to a pants type disposable diaper, which is excellent in a body fit and in a slip prevention, which has a good appearance and which is comfortable to wear.
2. Background Art
In the prior art, the pants type disposable diaper has an elastically extensible member arranged for the nonwoven fabric holding an absorber to absorb a body liquid, thereby to improve the fit on the body.
In Patent Document 1, for example, as shown in FIG. 18, there is disclosed a pants type disposable diaper, which includes a liquid-permeable top sheet 50, a liquid-impermeable back sheet 51, and an absorbent 52 arranged between those sheets 50 and 51. The two side portions of the front and the back are jointed to form a waist opening and a pair of leg openings. The disposable diaper is made to fit the body by arranging waist portion elastic members 48, 48, - - - , and so on along the waist opening, by arranging let portion elastic members 53, 53, - - - , and so on in the two leg openings substantially continuously along the peripheral edges, and by arranging hip portion elastic members 49, 49, - - - , and so on around the waist.
In case the elastic extensible members are arranged individually and independently at the three portions of the waist opening, the leg openings and the hip surrounding, as in the aforementioned disposable diaper, the minimum fit necessary for the paper diaper can be obtained but the satisfaction of the user is not always obtained.
In view of this problem, in Patent Document 2, as shown in FIG. 19, there is disclosed a disposable diaper, which includes a lower curved gather 54 of the trunk gathers as the gather for the abdomen side and/or the back side. The lower curved gather 54 is formed and curved at least to the crotch portion, and has its lowermost portion positioned lower than the uppermost end of the leg openings.
In Patent Document 3, on the other hand, there is disclosed a pants type disposable diaper, as shown in FIG. 20. In this disposable diaper including an absorbent body and an armoring member, first extensible elastic members 55, 55, - - - , and so on and second extensible elastic members 56, 56, - - - , and so on each composed of a plurality of extensible elastic materials are arranged on the front and the back of the armoring member. These extensible elastic members 55 - - - and 56 - - - individually extend from one side edge portion of one of the front and the back through the crotch portion to the other side edge portion, such that at least their portions are arranged along the paired leg surrounding openings and at a predetermined spacing at the crotch portion.
In order to further prevent the slip-down, in Patent Document 4, there is arranged a disposable pants type diaper, as shown in FIG. 21. This diaper is provided with a body, which includes a top sheet, a back sheet and an absorbent. This body is divided into an abdomen side portion and a back side portion. The two right and left side edge portions of the abdomen side portion and the back side portion are jointed and fixed to form a waist opening and leg openings. In the waist opening and the leg openings, there are arranged a waist elastic member 57 and leg elastic members 58, which form gathers substantially continuing along their whole peripheral edge portions. A plurality of hip surrounding elastic members 59, 59, - - - , and so on are arranged on the abdomen side and/or the back side of the hip surrounding elastic members. These hip surrounding elastic members 59, 59, - - - , and so on are arranged in such a displacement to the side of the crotch portion that the displacements of the hip surrounding elastic members 59, 59, - - - , and so on are the largest at the central portion of the abdomen side portion.
In Patent Document 5, moreover, there is disclosed a pants type paper diaper, as shown in FIG. 22. In this pants type paper diaper, elastic ridges 60, 60, - - - , and so on running in the transverse direction are arranged in a gather constitution having no intersection all over the front and the back of the pants. The elastic ridges 60, 60, - - - , and so on of the front and the back are substantially homogeneously arranged in the longitudinal direction on the right and left seal lines, and are more bulged and curved toward the crotch portion as they come closer to the intermediate portion.    Patent Document 1: JP-A-7-265357    Patent Document 2: JP-A-7-299094    Patent Document 3: JP-A-11-36103    Patent Document 4: JP-A-2001-258931    Patent Document 5: JP-A-2001-204762